Why is my HVAC making strange noises?

Rattling, banging, squealing, or hissing noises can signal specific issues. Rattling may indicate loose parts; banging often points to blower or motor problems; squealing can mean a worn belt; and hissing may suggest a refrigerant leak. It’s best to turn the system off and schedule a repair before the issue worsens. Ignoring unusual sounds can lead to costly damage or complete system failure.